Re: [PATCH v2 06/11] get_short_oid: sort ambiguous objects by type, then SHA-1

> From: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
>
> Here is what I mean by sorting during for_each_abbrev(). This seems to work for
> me, so I don't know what the issue is with this one-pass approach.
> [...]
> +static int sort_ambiguous(const void *a, const void *b)
> +{
> +	int a_type = oid_object_info(a, NULL);
> +	int b_type = oid_object_info(b, NULL);
> +	int a_type_sort;
> +	int b_type_sort;
> +
> +	/*
> +	 * Sorts by hash within the same object type, just as
> +	 * oid_array_for_each_unique() would do.
> +	 */
> +	if (a_type == b_type)
> +		return oidcmp(a, b);
> +
> +	/*
> +	 * Between object types show tags, then commits, and finally
> +	 * trees and blobs.
> +	 *
> +	 * The object_type enum is commit, tree, blob, tag, but we
> +	 * want tag, commit, tree blob. Cleverly (perhaps too
> +	 * cleverly) do that with modulus, since the enum assigns 1 to
> +	 * commit, so tag becomes 0.
> +	 */
> +	a_type_sort = a_type % 4;
> +	b_type_sort = b_type % 4;
> +	return a_type_sort > b_type_sort ? 1 : -1;
> +}
> +
>  static int get_short_oid(const char *name, int len, struct object_id *oid,
>  			  unsigned flags)
>  {
> @@ -451,6 +479,9 @@ int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
>  	find_short_object_filename(&ds);
>  	find_short_packed_object(&ds);
>
> +	QSORT(collect.oid, collect.nr, sort_ambiguous);
> +	collect.sorted = 1;
> +